Japanese Patent Application Publication No. 2016-127765 describes an inverter device that includes a first inverter and a second inverter. This inverter device changes a number of inverters to be energized, in accordance with output power. In other words, the inverter device energizes only the first inverter and does not energize the second inverter when output power is low, and energizes both of the first inverter and the second inverter when output power is high. Changing the number of inverters to be energized as such improves power conversion efficiency.